Several large multicenter randomized trials have established the usefulness of chemotherapy and/or tamoxifen in improving the disease-free survival in breast cancer patients with negative axillary nodes. In this group of patients, the optimal chemotherapy regimen is not known, and it is not clear whether the addition of tamoxifen to chemotherapy will provide any benefit over chemotherapy alone. This study will randomize patients who have recently had a lumpectomy and axillary dissection or mastectomy to one of four adjuvant therapy groups: chemotherapy consisting of cyclophosphamide, methotrexate, and 5FU either with or without tamoxifen; and chemotherapy consisting of cyclophosphamide and adriamycin either with or without tamoxifen. Patients will be followed for evidence of disease recurrence and for time of surival.